EAS aie ke Wi eee LR Whe une Se wet 
PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 209 
of the volumes of abdominal organs such as the kidney and 
spleen, and by judicious variation of the conditions of the 
experiment, by means of which the operation of a particular 
factor can be eliminated, one is generally able to ascertain to 
which of the factors concerned in the maintenance of the blood 
pressure the change is to be ascribed. 
The effect of several kinds of snake venom upon the blood 
pressure in the higher animals has been investigated. Brunton 
and Fayrer,! and Ragotzi,? worked with cobra poison. Mitchell, 
and Reichert? made a large series of experiments with the 
venoms of species of Crotalus and Ancistrodon, Daboia russellii, 
and also cobra. Feoktistow’st observations were made with the 
poisons of Crotalus and Vipera berus. 
Weir Mitchell and Reichert confirmed those results which had 
already been obtained by Brunton and Fayrer, with cobra poison ; 
and the more recent work of Feoktistow and Ragotzi entirely 
Supports the older observations as regards the main characteristics 
of the blood pressure curve after poisoning with either rattlesnake 
or cobra venoms. The work of Weir Mitchell and Reichert is the 
Most important as they pursued their investigations with the 
venoms of a very large number of different species of snakes, 
thereby giving us the opportunity of comparing the action, in this 
respect, of a variety of poisons. The results of these observers 
Possess the additional advantage of having been obtained from an 
admirably varied and extensive series of experiments. 
They found that when the venoms of all these species of serpents 
Were intravenously introduced, there was a distinct lowering of 
the blood pressure. It fell immediately after the injection, and 
Indeed Sometimes before this was completed ; and the fall was 
Benerally So marked as to indicate a most profound action of the 
Polson upon some part or parts of the circulatory apparatus. If 
the dose were not immediately fatal, the pressure gradually rose, 
but finally underwent a more or less steady decline until death. At 
1 ‘ 
MEW YF Loe. cit. 3 Lae clk ¥ Loe. HE 
N—July 3, 1995, 
